/*
 * Copyright (c) 2023. The BifroMQ Authors. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *    http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and limitations under the License.
 */

package com.baidu.bifromq.mqtt.handler;

import static com.baidu.bifromq.type.MQTTClientInfoConstants.MQTT_CHANNEL_ID_KEY;
import static com.baidu.bifromq.type.MQTTClientInfoConstants.MQTT_CLIENT_ID_KEY;
import static com.baidu.bifromq.type.MQTTClientInfoConstants.MQTT_USER_ID_KEY;

import com.baidu.bifromq.type.ClientInfo;

public class MQTTSessionIdUtil {
    public static int packetId(long seq) {
        return (int) (seq % 65535) + 1;
    }

    public static String userSessionId(ClientInfo info) {
        String requestClientId = info.getMetadataOrDefault(MQTT_CLIENT_ID_KEY, "");
        if (requestClientId.isEmpty()) {
            // if client id is assigned by server
            return info.getMetadataOrThrow(MQTT_USER_ID_KEY) + "/" + info.getMetadataOrDefault(MQTT_CHANNEL_ID_KEY, "");
        }
        return info.getMetadataOrThrow(MQTT_USER_ID_KEY) + "/" + requestClientId;
    }
}
